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EvolutionaryComparisonPipelineSmallTaxa.R
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EvolutionaryComparisonPipelineSmallTaxa.R
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##################
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# There is a copy of the GNU General Public License
# along with this program in the repository where it is located.
# Or view it directly here at http://www.gnu.org/licenses/
###################
# Authors and Contributions:
# This program was authored primarily by Matthew Orton.
# Contributions by Jacqueline May for lines 344-373,
# editing, formatting and testing of this program.
# Contributions by David Lee for lines 1662-1683,
# editing and formatting of this program.
# Contributions by Winfield Ly for editing and formatting of this program.
# Collaboration of Sarah Adamowicz (University of Guelph)
# in designing the analyses for this program as well as editing, formatting
# and testing of this program.
###################
# Program Purpose (Class-Level Analyses):
# This program will allow for the generation of latitudinally separated
# sister pairings and associated outgroupings from nearly any taxa
# (provided they have a suitable reference sequence
# and are not too large) and geographical region found on the BOLD API in one
# streamlined R pipeline! In this iteration of the pipeline, data is translated
# directly from a BOLD tsv file of the user's choosing to a dataframe in R.
# The generated sister pairs and outgroups can also be written to a csv or tsv,
# and the file will appear in the current working directory of R. Additionally,
# binomial and Wilcoxon tests can be performed on the signed relative branch
# lengths of the generated pairings, and a plot of the resultant relative
# outgroup distances can be generated for each class. A world map visualizing
# the latitudinally separated pairings for the taxon being run can also be
# generated using using the R visualization tool plotly.
# Larger taxa including various phyla can be run and will get broken down into
# classes, and sister pairs are sought within classes by default.
# ***This version of the program is intended for the smaller taxa under 10000
# BIN's in size.***
###################
# Guidelines and Tips on Using this Program:
# The versioning of R and R Studio is important and can influence the results
# of this program. At this time we can only guarantee full function of this
# program using R Studio versions 0.99.903 or 1.0.44 and R versions 3.3.1
# or 3.2.4.
# It is highly recommended that you use the IDE R Studio to run this program
# as this will provide a much more user friendly interface than just using R.
# This program is limited to using the BOLD API for download of taxonomic and
# sequence data. The taxa being tested with this program must use BIN
# identifiers as a means of identification; for instance, plants on the BOLD API
# cannot be run using this program since they do not use BIN identifiers.
# At this time, it is best not to run Arthropoda, Insecta, or Chordata
# in their entirety since these are all very large and computationally demanding
# and should be broken down into smaller sub-taxa.
# It is highly recommended that you save your workspaces frequently with large
# taxa in case of unexpected crashes within R Studio.
# Larger taxa consume a great deal of working memory and R is very memory
# intensive, so be mindful of the amount of available working memory you have
# available on your PC/Mac. As a general rule, every 1000 BIN's processed using
# this program requires roughly 1.5 Gb of working memory.
# It's probably a good idea to ensure RStudio is the only memory intensive
# application running when you run this program with a larger taxon. It is also
# important to note that some taxa are so large that running R Studio locally
# isnt really possible due to computational demands. However there is a great
# online version of R Studio using an EC2 instance on Amazon Web
# Services (cloud computing instance). There is a guide here that will show
# how to use this service:
# http://strimas.com/r/rstudio-cloud-1/
# Entries on BOLD which do not at least have class-level classification
# will be filtered out since the program cannot properly categorize these.
# You do not have to worry about entries missing certain pieces of data,
# for example latitude coordinates, sequence data etc.
# The script will filter these records out automatically.
# There are two options for parsing the tsv.
# You can either download the tsv directly from the BOLD API,
# or you can use a tsv you have previously downloaded. You can also save your
# workspace once a TSV is downloaded so you don't have to download it again.
# When testing a taxon for the first time, you will have to ensure that you have
# a suitable reference sequence for it and ensure that it is inserted into the
# dfRefSeq dataframe in Section 5 of the code. Ensure that you keep the entire
# sequence in one line; breaking it up on to separate lines will add a new line
# character.
# The reference sequence is a high-quality sequence from a given taxon, which is
# used as the basis for the first alignment step. As well, the reference
# sequence is used to trim all sequences to the same length for analysis. To
# insert a sequence to the dfRefSeq dataframe, simply add another taxon and
# sequence in quotation marks in the refseq dataframe commented in the
# reference sequence section.
# Some tips for using the BOLD API since this is what is used to grab
# the relevant data needed from BOLD:
# To see details on how to use the BOLD API,
# go to http://www.boldsystems.org/index.php/resources/api?type=webservices
# We can add additional restrictions to the url, for example
# &instituiton=Biodiversity Institute of Ontario|York University or
# &marker=COI-5P if you want to specifiy an institution.
# geo=all in the url means global but geo can be geo=Canada, for example.
# We can also use | modifier in the url. For example, &geo=Canada|Alaska
# would give data for both Canada and Alaska,
# or taxon=Aves|Reptilia would yield data for both Aves and Reptilia.
#################
# Important Dataframes:
# dfPVal gives the p-values for both the binomial test and Wilcoxon tests for
# all classes (that have pairings) and each class separately.
# dfPairingResultsSummary shows a more user-friendly summation of the
# pairing results.
# dfRelativeBranchLength shows the relative distances to the outgroup for each
# pairing including pseudoreplicates.
# dfPairingResultsL1L2 is a more detailed finalized dataframe that contains all
# of the finalized pairings and outgroupings and all relevant details for them.
# dfPairingResultsL1 and dfPairingResultsL2 represent dataframes for each
# lineage of each pairing, respectively.
# dfInitial is the dataframe first produced by the import from BOLD and is
# filtered by latitude, bin_uri, N content, gap content, and sequence length.
# dfOutGroupL1 and L2 contain the associated outgroupings only
# (for each lineage), but each one does have a column indicating the pairing
# with which it is associated.
# dfCentroid contains centroid sequences for all BINs with more than one member.
# dfNonCentroid contains all BINs that only have one member and thus do not need
# centroid sequences.
# dfAllSeq is simply dfNonCentroid and dfCentroid combined together in one
# dataframe.
# dfGeneticDistanceStack is all genetic distance matrices concatenated into one
# long column of values. It is used to grab bin_uri's and distances for each
# pairing and assist in determining outgroup bin_uri's and distances.
# dfRefSeq shows various taxa with a suitable reference sequence that has been
# found for them.
# dfPseudoRep shows each separate ingroup pairing number of each set of
# pseudoreplicates along with its respective relative outgroup distance.
# dfPseudoRepAverage shows the averaged relative branch lengths for each set of
# pseudoreplicates in dfPseudoRep.
##################
# Important Variables:
# alignment2 will show a truncated alignment of each class before divergent
# sequences are removed. (For example, typing alignment2[1] will show the first
# alignment performed.) Note that the console will not show the full alignment,
# to view the full alignment you must convert and export to FASTA format.
# To export to FASTA format and view the full alignment, please see the commands
# in section 6 of the code.
# alignmentFinal will show a truncated final alignment of each class after
# divergent sequences are removed. (For example, typing alignmentFinal[1] will
# show the first alignment performed.) Note that the console will not show the
# full alignment, to view the full alignment you must convert and export to
# FASTA format. To export to FASTA format and view the full alignment, please
# see the commands in section 7 of the code.
# alignmentFinalTrim will show a truncated final alignment of each class that is
# also trimmed by the reference sequence. (For example, typing
# alignmentFinalTrim[1] will show the first trimmed alignment performed.)
# Note that the console will not show the full alignment, to view the full
# alignment you must convert to FASTA format. To export to FASTA format and view
# the full alignment, please see the commands in section 8 of the code.
# binomialTestOutGroup shows the results of the binomial test.
# wilcoxonTestOutgroup shows the results of the Wilcoxon test.
# mapLayout is a variable that will allow for customization of the world map
# for map plotting using the visualization tool Plotly.
#################
# Packages Required:
# Note that once you have installed the packages (first time running program),
# you only have to run the libraries again each time you open up R Studio or
# restart R Studio.
# Therefore, remove the "#" symbol in front of the lines for installing the
# packages the first time running the script.
# We need the foreach package for several functions that require iteration
# over dataframe rows.
# install.packages("foreach")
library(foreach)
# For genetic distance determination using the TN93 model, the ape package is
# required.
# install.packages("ape")
library(ape)
# The readr package will speed up parsing of the tsv file using the
# read_tsv function.
# install.packages("readr")
library(readr)
# For sequence alignments we need the biostrings (DNAStringSet function)
# and muscle libraries, as follows:
# source("https://bioconductor.org/biocLite.R")
# biocLite("Biostrings")
# biocLite("muscle")
library(Biostrings)
library(muscle)
# For the calculation of overlapping latitude regions we need the
# Desctools package.
# The Desctools package allows us to use the Overlap function which can
# calculate overlap regions between BINs based on the maximum and minimum
# latitudinal ranges of each BIN.
# install.packages("DescTools")
library(DescTools)
# Adding the data tables package for data table merging of outgroup BIN data
# with pairing results BIN data in the pairing result section.
# install.packages("data.table")
library(data.table)
# For plotting of relative outgroup distances between lineages we will also need
# ggplot2.
# install.packages ("ggplot2")
require(ggplot2)
# dplyr is required if this is not already installed.
# install.packages("dplyr")
library(dplyr)
# As a pre-requisite package to plotly we need the colorspace package.
# install.packages("colorspace")
library(colorspace)
# Prerequisite for the plotly package.
# install.packages("jsonlite")
library(jsonlite)
# plotly package used for map plotting functionality.
# install.packages("plotly")
library(plotly)
# Excel writer for output of results to an excel file
# install.packages("xlsx")
library(xlsx)
#################
# R Commands:
# Section 1: TSV Parsing
# In this section the intial TSV of the desired taxon is parsed from the BOLD
# database API.
# First we download the TSV and convert it into a dataframe. The URL below is
# what is modified by the user and will determine the taxon, geographic region,
# etc. Example: taxon=Aves$geo=all, see above in Guidelines and Tips for more
# information on how to use the BOLD API.
# The read_tsv function has been modified to select only certain columns to save
# on downloading time:
dfInitial <- read_tsv("http://www.boldsystems.org/index.php/API_Public/combined?taxon=&geo=all&format=tsv")[,
c('recordID', 'bin_uri','phylum_taxID','phylum_name',
'class_taxID','class_name','order_taxID',
'order_name','family_taxID','family_name',
'subfamily_taxID','subfamily_name','genus_taxID',
'genus_name','species_taxID','species_name',
'lat','lon','nucleotides','markercode')]
# If you want to run pre downloaded BOLD TSV's to avoid downloading of the same
# tsv multiple times, this will let you choose a path to that TSV and parse.
# Uncomment and run these commands:
# tsvParseDoc <- file.choose()
# dfInitial <- read_tsv(tsvParseDoc)[,
# c('recordID', 'bin_uri','phylum_taxID','phylum_name',
# 'class_taxID','class_name','order_taxID',
# 'order_name','family_taxID','family_name',
# 'subfamily_taxID','subfamily_name','genus_taxID',
# 'genus_name','species_taxID','species_name',
# 'lat','lon','nucleotides','markercode')]
# ***Keep in mind you can also save your R workspace to avoid redownloading
# BOLD TSV's.***
###################
# Section 2: Dataframe Filtering and Reorganization
# In this section, the dataframe is filtered according to latitude,
# sequence quality, and sequence length.
# The initial dataframe is also reorganized.
# Renaming record id column.
colnames(dfInitial)[1] <- "record_id"
# Removing sequences with marker codes other than COI-5P.
containCOI <- grep( "COI-5P", dfInitial$markercode)
dfInitial<-dfInitial[containCOI,]
# Removing sequences with no latitude values. We are filtering according to lat
# since we only really need lat for the analysis.
containLat <- grep( "[0-9]", dfInitial$lat)
dfInitial<-dfInitial[containLat,]
# Next, we have to convert the lat column to num instead of chr type. This will
# become important later on for median latitude determination.
latNum <- with(dfInitial, as.numeric(as.character(lat)))
dfInitial$latNum <- latNum
# We will do lon as well for map plotting using plotly.
lonNum <- with(dfInitial, as.numeric(as.character(lon)))
dfInitial$lonNum <- lonNum
# We next identify records missing a BIN assignment and eliminate rows with
# missing bin_uri's since the presence of a BIN designation is an indicator of
# sequence length and quality. As well, we use BINs later in the analysis.
# This is achieved by using grep by colon, since every record with a BIN
# identifier will have this.
containBin <- grep( "[:]", dfInitial$bin_uri)
dfInitial <- dfInitial[containBin,]
# We next get rid of any records that don't have sequence data.
# Sometimes there are records that bear a BIN but for which the sequence was
# subsequently deleted. This could occur if a record had a sequence and the
# record holder later deleted the sequence, e.g. due to suspected contamination.
containNucleotides <- grep( "[ACGT]", dfInitial$nucleotides)
dfInitial <- dfInitial[containNucleotides,]
# Next, we filter out high gap content and N content to ensure high sequence
# quality.
# First, we need to convert nucleotides to chr type.
dfInitial$nucleotides <- with(dfInitial, (as.character(nucleotides)))
# Cut off starting Ns and gaps (large portions of Ns and gaps occur at the start
# of a sequence).
startNGap <- sapply(regmatches(dfInitial$nucleotides, gregexpr("^[-N]",
dfInitial$nucleotides)), length)
startNGap <- foreach(i=1:nrow(dfInitial)) %do%
if (startNGap[[i]] > 0) {
split <- strsplit(dfInitial$nucleotides[i], "^[-N]+")
dfInitial$nucleotides[i] <- split[[1]][2]
}
# Cut off ending Ns and gaps (large portions of Ns and gaps occur at the end of
# a sequence).
endNGap <- sapply(regmatches(dfInitial$nucleotides, gregexpr("[-N]$",
dfInitial$nucleotides)), length)
endNGap <- foreach(i=1:nrow(dfInitial)) %do%
if (endNGap[[i]] > 0) {
split <- strsplit(dfInitial$nucleotides[i], "[-N]+$")
dfInitial$nucleotides[i] <- split[[1]][1]
}
# This will give the number of positions where an *internal* N or gap is found
# for each sequence.
internalNGap <- sapply(regmatches(dfInitial$nucleotides, gregexpr("[-N]",
dfInitial$nucleotides)), length)
# We then loop through each sequence to see if the number of Ns or gaps is
# greater than 1% (0.01) of the total sequence length.
internalNGap <- foreach(i=1:nrow(dfInitial)) %do%
which((internalNGap[[i]] / nchar(dfInitial$nucleotides[i]) > 0.01 ))
nGapCheck <- sapply( internalNGap , function (x) length( x ) )
nGapCheck <- which(nGapCheck > 0)
# Subset out these higher gap and N content sequences.
dfInitial <- dfInitial[-nGapCheck, ]
# Filter out sequences less than 640 bp and greater than 1000 bp since these
# sequence length extremes can interfere with the alignment,
# and this also helps to standardize sequence length against the reference
# sequences, for consistency in subsequent analyses.
sequenceLengths <- nchar(gsub("-", "", dfInitial$nucleotides))
sequenceLengthCheck <- which(sequenceLengths > 1000 | sequenceLengths < 640)
dfInitial <- dfInitial[-sequenceLengthCheck,]
# Modifying BIN column slightly to remove "BIN:"
dfInitial$bin_uri <- substr(dfInitial$bin_uri, 6 , 13)
# Dataframe Reorganization
dfInitial <- (dfInitial[,c("record_id","bin_uri","phylum_taxID","phylum_name",
"class_taxID","class_name","order_taxID","order_name"
,"family_taxID","family_name","subfamily_taxID",
"subfamily_name","genus_taxID","genus_name",
"species_taxID","species_name","nucleotides",
"latNum","lonNum")])
###################
# Section 3: BIN Stats and Median Latitude/Longitude Determination per BIN
# In this section, the median latitude is determined for each BIN as well as
# other important pieces of information including number of record ids within
# each BIN and the latitudinal min and max of each BIN.
# First we can make a smaller dataframe with the columns we want for each BIN:
# bin_uri, latnum, lonnum, record_id, and nucleotides.
dfBinList <-
(dfInitial[,c("record_id","bin_uri","latNum","lonNum","nucleotides")])
# We convert latitudes to absolute values before median latitude values are
# calculated on dfBinList.
dfBinList$latNumAbs <- abs(dfBinList$latNum)
# Lon remains untouched as it is not needed for the analysis.
# Create groupings by BIN with each grouping representing a different bin_uri.
# Each element of this list represents a BIN with subelements representing the
# various columns of the initial dataframe created, and the information is
# grouped by BIN.
binList <- lapply(unique(dfBinList$bin_uri), function(x)
dfBinList[dfBinList$bin_uri == x,])
# Now determine the median latitude for each BIN based on absolute values.
medianLatAbs <- sapply( binList , function(x) median( x$latNumAbs ) )
# Calculating median lat based upon the original latitude values,
# for mapping purposes only.
medianLatMap <- sapply( binList , function(x) median( x$latNum ) )
# We also need a median longitude for map plotting.
medianLon <- sapply( binList , function(x) median( x$lonNum ) )
# We can also take a few other important pieces of data regarding each BIN using
# sapply, including number of record_ids within each BIN and the latitudinal min
# and max of each BIN.
latMin <- sapply( binList , function(x) min( x$latNum ) )
latMax <- sapply( binList , function(x) max( x$latNum ) )
binSize <- sapply( binList , function (x) length( x$record_id ) )
# Dataframe of our median lat values. This will be used in our final dataframe.
dfLatLon <- data.frame(medianLatAbs)
# Adding bin_uri, latMin, latMax, binSize and medianLatMap to dataframe.
# medianLatMap is the median latitude without conversion to an absolute value
# and is used purely for mapping purposes.
dfLatLon$bin_uri <- c(unique(dfInitial$bin_uri))
dfLatLon$medianLon <- c(medianLon)
dfLatLon$latMin <- c(latMin)
# Convert to absolute value for latMin and latMax.
dfLatLon$latMin <- abs(dfLatLon$latMin)
dfLatLon$latMax <- c(latMax)
dfLatLon$latMax <- abs(dfLatLon$latMax)
dfLatLon$binSize <- c(binSize)
dfLatLon$medianLatMap <- c(medianLatMap)
# Merging LatLon to BinList for the sequence alignment step.
dfBinList <- merge(dfBinList, dfLatLon, by.x = "bin_uri", by.y = "bin_uri")
# Also reordering dfLatLon by bin_uri for a step later on.
dfLatLon <- dfLatLon[order(dfLatLon$bin_uri),]
###################
# Section 4: Selecting a Centroid Sequence Per BIN
# A single Barcode Index Number (BIN) can contain many record ids and sequences.
# In order to simplify the analyses, we select one sequence per BIN.
# To do this we are determining the centroid sequence for each BIN.
# Centroid Sequence: BIN sequence with minimum average pairwise distance to all
# other sequences in a given BIN.
# First we have to subset dfBinList to find BINs with more than one member since
# these BINs will need centroid sequences.
largeBin <- which(dfBinList$binSize > 1)
# If there is at least one BIN with more than one member, then a dataframe
# dfCentroid will be created with those BINs.
if (length(largeBin) > 0) {
dfCentroid <- dfBinList[largeBin,]
# Also subset dfLatLon down to number of BINs in dfInitial
dfLatLon <- subset(dfLatLon, dfLatLon$bin_uri %in% dfCentroid$bin_uri)
# Also need to find the number of unique BINs in dfCentroid.
binNumberCentroid <- unique(dfCentroid$bin_uri)
binNumberCentroid <- length(binNumberCentroid)
# We also have to create another separate dataframe with BINs that only have
# one member called dfNonCentroid.
dfNonCentroid <- dfBinList[-largeBin, ]
# We then take the dfCentroid sequences and break it down into a list with
# each element being a unique BIN.
largeBinList <- lapply(unique(dfCentroid$bin_uri),
function(x) dfCentroid[dfCentroid$bin_uri == x,])
# Extract record id from each BIN.
largeBinRecordId <- sapply( largeBinList , function(x) ( x$record_id ) )
# Convert all of the sequences in the largeBinList to dnaStringSet format for
# the alignment step.
dnaStringSet1 <-
sapply( largeBinList, function(x) DNAStringSet(x$nucleotides) )
# name DNAStringSet with the record ids.
for (i in seq(from = 1, to = binNumberCentroid, by = 1)) {
names(dnaStringSet1[[i]]) <- largeBinRecordId[[i]]
}
# Multiple sequence alignment using the muscle package.
# Refer here for details on package:
# https://www.bioconductor.org/packages/release/bioc/html/muscle.html
# Run a multiple sequence alignment on each element of the dnaStringSet1 list
# Using diags = TRUE with Muscle command to speed up alignment of each BIN.
alignment1 <- foreach(i=1:binNumberCentroid) %do%
muscle::muscle(dnaStringSet1[[i]], maxiters = 3, diags = TRUE, gapopen = -3000)
# We can then convert each alignment to DNAbin format.
dnaBINCentroid <-
foreach(i=1:binNumberCentroid) %do% as.DNAbin(alignment1[[i]])
# Then, we perform genetic distance determination with the TN93 model on each
# DNAbin list.
geneticDistanceCentroid <- foreach(i=1:binNumberCentroid) %do%
dist.dna(dnaBINCentroid[[i]], model = "TN93", as.matrix = TRUE,
pairwise.deletion = TRUE)
# The centroid sequence can be determined from the distance matrix alone.
# It is the sequence in a bin with minimum average pairwise distance to all
# other sequences in its BIN.
centroidSeq <- foreach(i=1:binNumberCentroid) %do%
which.min(rowSums(geneticDistanceCentroid[[i]]))
centroidSeq <- unlist(centroidSeq)
centroidSeq <- names(centroidSeq)
centroidSeq <- as.numeric(centroidSeq)
# Subset dfCentroid by the record ids on this list.
dfCentroid <- subset(dfCentroid, record_id %in% centroidSeq)
# Append our noncentroid to our centroid sequences. We will make a new
# dataframe for this - dfAllSeq.
# Now we have all of the sequences we need for the next alignment of all
# sequences, with one sequence representing each BIN.
dfAllSeq <- rbind(dfCentroid, dfNonCentroid)
# We can then merge this with dfInitial to get all of the relevant data we
# need, merging to dfInitial to gain all the relevant taxanomic data.
dfAllSeq <- merge(dfAllSeq, dfInitial, by.x = "record_id", by.y = "record_id")
# Renaming and reorganizing the dataframe.
dfAllSeq <-
(dfAllSeq[,c("bin_uri.x","binSize","record_id","phylum_taxID","phylum_name",
"class_taxID","class_name","order_taxID","order_name",
"family_taxID","family_name","subfamily_taxID",
"subfamily_name","genus_taxID","genus_name","species_taxID",
"species_name","nucleotides.x","medianLatAbs","medianLatMap",
"latMin","latMax","medianLon")])
colnames(dfAllSeq)[1] <- "bin_uri"
colnames(dfAllSeq)[18] <- "nucleotides"
# Adding an index column to reference later with Pairing Results dataframe.
dfAllSeq$ind <- row.names(dfAllSeq)
# Deleting any possible duplicate entries.
dfAllSeq <- (by(dfAllSeq, dfAllSeq["bin_uri"], head, n = 1))
dfAllSeq <- Reduce(rbind, dfAllSeq)
} else {
# Else if there are no BINs with more than one member then we would simply
# merge latlon with initial to get dfAllSeq and thus all of the sequences we
# want.
dfAllSeq <- merge(dfLatLon, dfInitial, by.x = "bin_uri", by.y = "bin_uri")
dfAllSeq <-
(dfAllSeq[,c("bin_uri.x","binSize","record_id","phylum_taxID","phylum_name",
"class_taxID","class_name","order_taxID","order_name",
"family_taxID","family_name","subfamily_taxID",
"subfamily_name","genus_taxID","genus_name","species_taxID",
"species_name","nucleotides.x","medianLatAbs","medianLatMap",
"latMin","latMax","medianLon")])
dfAllSeq$ind <- row.names(dfAllSeq)
}
# To simplify the number of dataframes, can remove dfLatLon and dfBinList since
# these are redundant.
rm(dfBinList)
rm(dfLatLon)
###################
# Section 5: Creation of Reference Sequence Dataframe
# In this section we establish reference sequences that will be used in the
# final alignment for appropriate trimming of the alignment to a standard
# sequence length of 620 bp.
# Currently, the script is finetuned for reference sequences of 658 bp of
# the barcode region of the cytochrome c oxidase subunit I (COI) gene. Minor
# modifications to the alignment settings or trimming amount would be needed to
# use sequences of different lengths or different genes.
# We selected reference sequences that fell between the primers for COI
# by Folmer et al. (1994):
# Folmer O, M, Black WH, Lutz R, Vrijenhoek R (1994) DNA primers for
# amplification of mitochondrial cytochrome C oxidase subunit I from metazoan
# invertebrates. Molecular Marine Biology and Biotechnology 3: 294-299.
# In DNA barcoding studies, many taxonomic groups are amplified by these primers
# or by variants of these primers that bind at the same position. For most taxa,
# the reference sequences were exactly 658 bp in length. For certain taxa
# (e.g. Bivalvia), the length differed from 658 bp due to amino acid indels, but
# the same start and end point, as verified using an amino acid alignment,
# was used.
# Manual input of reference sequences into dfRefSeq dataframe
dfRefSeq <- data.frame(taxa = c(""),
nucleotides = c(""))
colnames(dfRefSeq)[2] <- "nucleotides"
dfRefSeq$nucleotides <- as.character(dfRefSeq$nucleotides)
# Symmetrical trimming of the references to a standard 620 bp from 658 bp.
# A different trimming length could be used, depending upon the distribution of
# sequence lengths in a particular taxon.
dfRefSeq$nucleotides <-
substr(dfRefSeq$nucleotides, 20, nchar(dfRefSeq$nucleotides) - 19)
# Check of sequence length.
dfRefSeq$seqLength <- nchar(dfRefSeq$nucleotides)
# Subset dfAllSeq by entries in the reference sequence dataframe.
dfAllSeq <- subset(dfAllSeq, dfAllSeq$class_name %in% dfRefSeq$taxa)
# Break dfAllSeq down into the various classes.
taxaListComplete <- lapply(unique(dfAllSeq$class_taxID),
function(x) dfAllSeq[dfAllSeq$class_taxID == x,])
# Revise dfRefSeq dataframe to reflect this.
classList <- foreach(i=1:nrow(dfRefSeq)) %do%
unique(taxaListComplete[[i]]$class_name)
classList <- unlist(classList)
# This command will ensure the reference sequence dataframe is in the same order
# as the dfAllSeq dataframe.
dfRefSeq <- dfRefSeq[match(classList, dfRefSeq$taxa),]
###################
# Section 6: Preliminary Alignment with Muscle and Pairwise Distance Matrix with
# the TN93 Model to Identify and Remove Divergent Sequences
# In this section we want to eliminate sequences that are too divergent in
# pairwise distance by doing an initial alignment and distance matrix.
# Highly divergent sequences can cause major gaps in the alignment and
# inaccurate pairwise distances between sequences.
# As well, the analysis further below compares latitudinally separated BINs that
# are relatively closely related.
# Using the Muscle alignment algorithm and the TN93 model.
# This ensures the final alignment will only be using sequences that are closely
# related to some others in pairwise distance.
# Extraction of Sequences from taxaListComplete for the alignment.
classSequences <- foreach(i=1:nrow(dfRefSeq)) %do%
taxaListComplete[[i]]$nucleotides
# Extraction of BINs from taxalist for the alignment.
classBin <- foreach(i=1:nrow(dfRefSeq)) %do% taxaListComplete[[i]]$bin_uri
# Conversion to DNAStringSet format.
dnaStringSet2 <-
foreach(i=1:nrow(dfRefSeq)) %do% DNAStringSet(classSequences[[i]])
# Naming the DNAStringSet with the appropriate bin_uri's.
for (i in seq(from = 1, to = nrow(dfRefSeq), by = 1)) {
names(dnaStringSet2[[i]]) <- classBin[[i]]
}
# Multiple sequence alignment using muscle package on the dnaStringSet2 list for
# each class.
# Refer here for details on package:
# https://www.bioconductor.org/packages/release/bioc/html/muscle.html
# This could take several minutes to hours depending on the taxa.
# Using default settings of package, the muscle command can detect DNA is being
# used and align accordingly.
# The settings can be modified, if needed, depending upon the size of the
# data set to be aligned and the patterns of sequence divergence in given data
# set.
alignment2 <- foreach(i=1:nrow(dfRefSeq)) %do%
muscle(dnaStringSet2[[i]], maxiters = 3, diags = TRUE, gapopen = -3000)
# To check each preliminary alignment (each class) and output the preliminary
# alignments to FASTA format, uncomment and run these three commands:
# classFileNames <- foreach(i=1:nrow(dfRefSeq)) %do%
# paste("alignmentPrelim",dfRefSeq$taxa[i],".fas",sep="")
# alignmentPrelimFasta <- foreach(i=1:nrow(dfRefSeq)) %do%
# DNAStringSet(alignment2[[i]])
# foreach(i=1:nrow(dfRefSeq)) %do%
# writeXStringSet(alignmentPrelimFasta[[i]],
# file=classFileNames[[i]], format = "fasta", width = 1500)
# ***FASTA files will show up in working directory of R and be named according
# to the appropriate class being aligned.
# For instance the class Polychaeta would show up as the file
# alignmentPrelimPolychaeta.fas.***
# Conversion to DNAbin format before using pairwise distance matrix.
dnaBin <- foreach(i=1:length(taxaListComplete)) %do% as.DNAbin(alignment2[[i]])
# Details on each model can be found here:
# https://cran.rstudio.com/web/packages/ape/index.html
# We are using the TN93 model for our data, but the model selection can be
# altered.
matrixGeneticDistance <- foreach(i=1:length(taxaListComplete)) %do%
dist.dna(dnaBin[[i]], model = "TN93",
as.matrix = TRUE, pairwise.deletion = TRUE)
# Conversion to dataframe format.
geneticDistanceMatrixList <- foreach(i=1:length(taxaListComplete)) %do%
as.data.frame(matrixGeneticDistance[i])
# Putting it into a stack (each column concatenated into one long column of
# indexes and values)so it can be easily subsetted.
geneticDistanceStackList <- foreach(i=1:length(taxaListComplete)) %do%
stack(geneticDistanceMatrixList[[i]])
# Identification and removal of divergent sequences, a divergent sequence being
# one that is greater than 0.15 in pairwise distance to all other sequences.
# Finding all sequences between 0.15 and 0 distance.
# This command will remove divergent sequences which do not have pairwise
# distances between 0.15 and 0.
divergentSequencesRemove <- foreach(i=1:length(taxaListComplete)) %do%
which(geneticDistanceMatrixList[[i]] <= 0.15 &
geneticDistanceMatrixList[[i]] > 0)
# Subsetting the distance stack by BINs meeting this criteria.
divergentSequencesRemove <- foreach(i=1:length(taxaListComplete)) %do%
geneticDistanceStackList[[i]][c(divergentSequencesRemove[[i]]), ]
# Grabbing all BINs from this stack that meet this criteria and converting to
# character type.
divergentSequencesRemove <- foreach(i=1:length(taxaListComplete)) %do%
as.character(unique(divergentSequencesRemove[[i]]$ind))
###################
# Section 7: Finalized Alignment with Addition of Reference Sequence
# In this section we can perform the final alignment after divergent sequences
# have been removed and the addition of a reference sequence.
# Subset taxalist by BINs meeting 0.15 criteria so no divergent sequences are
# present.
taxaListComplete <- foreach(i=1:length(taxaListComplete)) %do%
subset(taxaListComplete[[i]], taxaListComplete[[i]]$bin_uri %in%
divergentSequencesRemove[[i]])
# Extract sequences and bin_uri from each class.
classBin <- foreach(i=1:nrow(dfRefSeq)) %do% taxaListComplete[[i]]$bin_uri
classSequences <-
foreach(i=1:nrow(dfRefSeq)) %do% taxaListComplete[[i]]$nucleotides
classSequencesNames <- classBin
# Take our reference sequences.
alignmentRef <- as.character(dfRefSeq$nucleotides)
dfRefSeq$reference <- "reference"
# Name our reference as reference for each class so it can be identified as such
# in the alignment.
alignmentRefNames <- dfRefSeq$reference
# Merge our reference sequences with each of our class sequences.
alignmentSequencesPlusRef <- foreach(i=1:nrow(dfRefSeq)) %do%
append(classSequences[[i]], alignmentRef[[i]])
# Merge the names together.
alignmentNames <- foreach(i=1:nrow(dfRefSeq)) %do%
append(classSequencesNames[[i]], alignmentRefNames[[i]])
# Converting all sequences in dfAllSeq plus reference to DNAStringSet format,
# the format required for the alignment.
dnaStringSet3 <- foreach(i=1:nrow(dfRefSeq)) %do%
DNAStringSet(alignmentSequencesPlusRef[[i]])
# Name the DNAStringSet List with the appropriate BIN uri's.
for (i in seq(from=1, to=nrow(dfRefSeq), by = 1)){
names(dnaStringSet3[[i]]) <- alignmentNames[[i]]
}
# Multiple sequence alignment using muscle package on each element of the
# dnaStringSet2 list for each class.
# Refer here for details on package:
# https://www.bioconductor.org/packages/release/bioc/html/muscle.html
# This could take several minutes to hours depending on the taxa.
# Using default parameters, muscle will detect DNA is being used and will
# align accordingly.
alignmentFinal <- foreach(i=1:nrow(dfRefSeq)) %do%
muscle(dnaStringSet3[[i]], maxiters = 3, diags = TRUE, gapopen = -3000)
# To check each final alignment (each class) and output the final alignments to
# FASTA format, uncomment and run these three commands:
# classFileNames2 <- foreach(i=1:nrow(dfRefSeq)) %do%
# paste("alignmentFinal", dfRefSeq$taxa[i], ".fas", sep="")
# alignmentFinalFasta <- foreach(i=1:nrow(dfRefSeq)) %do%
# DNAStringSet(alignmentFinal[[i]])
# foreach(i=1:nrow(dfRefSeq)) %do%
# writeXStringSet(alignmentFinalFasta[[i]], file=classFileNames2[[i]],
# format="fasta", width=1500)
# ***FASTA files will show up in working directory of R and be named according
# to the appropriate class being aligned. For instance the class Polychaeta
# would show up as the file alignmentFinalPolychaeta.fas.***
###################
# Section 8: Sequence Trimming of Finalized Alignment According to the Reference
# Sequence
# In this section, the final alignment generated is now trimmed according to the
# position of the reference in the alignment. This step ensures that a
# consistent genetic region is used for the subsequent distance calculations.
# For trimming of the sequences we have to determine where in the alignment the
# reference sequence is and determine its start and stop positions relative to
# the other sequences. We can then use these positions to trim the rest of the
# sequences in the alignment.
refSeqPos <- foreach(i=1:nrow(dfRefSeq)) %do%
which(alignmentFinal[[i]]@unmasked@ranges@NAMES == "reference")
refSeqPos <- foreach(i=1:nrow(dfRefSeq)) %do%
alignmentFinal[[i]]@unmasked[refSeqPos[[i]]]
# Finding start position by searching for the first nucleotide position of the
# reference sequence.
refSeqPosStart <- foreach(i=1:nrow(dfRefSeq)) %do%
regexpr("[ACTG]", refSeqPos[[i]])
refSeqPosStart <- as.numeric(refSeqPosStart)
# Finding last nucleotide position of the reference sequence.
refSeqPosEnd <- foreach(i=1:nrow(dfRefSeq)) %do%
(nchar(dfRefSeq$nucleotides[i]) + refSeqPosStart[i])
refSeqPosEnd <- as.numeric(refSeqPosEnd)
# Then we can substr the alignment by these positions to effectively trim the
# alignment.
alignmentFinalTrim <- foreach(i=1:nrow(dfRefSeq)) %do%
substr(alignmentFinal[[i]], refSeqPosStart[i] + 1, refSeqPosEnd[i])
# In Mollusca it has been found that some sequences were shorter
# than reference sequence length when not counting gaps. These next few
# commands can be uncommented for Mollusca to filter out sequences less than
# 600 bp (counting nucleotides only) after trimming
# according to the reference:
# sequenceLengths2 <- foreach(i=1:nrow(dfRefSeq)) %do%
# nchar(gsub("-", "", alignmentFinalTrim[[i]]))
# sequenceLengthCheck2 <- foreach(i=1:nrow(dfRefSeq)) %do%
# which(sequenceLengths2[[i]] > 600)
# alignmentFinalTrim <- foreach(i=1:nrow(dfRefSeq)) %do%
# alignmentFinalTrim[[i]][sequenceLengthCheck2[[i]]]
# To check each final trimmed alignment (each class) and output the final
# trimmed alignments to FASTA format, uncomment and run these three commands:
# classFileNames3 <- foreach(i=1:nrow(dfRefSeq)) %do%
# paste("alignmentFinalTrim", dfRefSeq$taxa[i], ".fas", sep="")
# alignmentFinalTrimFasta <- foreach(i=1:nrow(dfRefSeq)) %do%
# DNAStringSet(alignmentFinalTrim[[i]])
# foreach(i=1:nrow(dfRefSeq)) %do%
# writeXStringSet(alignmentFinalTrimFasta[[i]], file=classFileNames3[[i]],
# format="fasta", width=658)
# ***FASTA files will show up in working directory of R and be named according
# to the appropriate class being aligned. For instance the class Polychaeta
# would show up as the file alignmentFinalTrimPolychaeta.fas.***
# Again, convert to dnaStringSet format.
dnaStringSet4 <- foreach(i=1:nrow(dfRefSeq)) %do%
DNAStringSet(alignmentFinalTrim[[i]])
# Establish where the reference sequence is in each alignment for removal of
# the reference from further analysis.
refSeqRemove <- foreach(i=1:nrow(dfRefSeq)) %do%
which(dnaStringSet4[[i]]@ranges@NAMES == "reference")
# We also have to check dnaStringSet4 for alignments that only contain a
# reference sequence and remove these.
alignmentCheck <- foreach(i=1:nrow(dfRefSeq)) %do%
which(length(dnaStringSet4[[i]]) == 1)
alignmentCheck <- which(alignmentCheck > 0)
# Subset dnaStringSet4, taxalistcomplete, alignmentFinalTrim and refSeqRemove by
# the alignment check.
if (length(alignmentCheck > 0)) {
dnaStringSet4 <- dnaStringSet4[-alignmentCheck]
taxaListComplete <- taxaListComplete[-alignmentCheck]
alignmentFinalTrim <- alignmentFinalTrim[-alignmentCheck]
refSeqRemove <- refSeqRemove[-alignmentCheck]
}
# Removal of references from both dnaStringSet4 and alignmentFinalTrim.
dnaStringSet4 <- foreach(i=1:length(taxaListComplete)) %do%
subset(dnaStringSet4[[i]][-refSeqRemove[[i]]])
alignmentFinalTrim <- foreach(i=1:length(taxaListComplete)) %do%
alignmentFinalTrim[[i]][-refSeqRemove[[i]]]
###################
# Section 9: Pairwise Distance Determination with the TN93 Model of Finalized
# Alignment
# In this section we do the final pairwise distance determination step using the
# TN93 model, before initial pairings can be generated.
# Conversion to DNAbin format before using genetic distance matrix.
dnaBin2 <- foreach(i=1:length(taxaListComplete)) %do%
as.DNAbin(dnaStringSet4[[i]])
# Once again using the TN93 model for pairwise distance computation, this time
# from the 3rd alignment after divergent sequences have been removed and after
# trimming according to the reference sequences.
matrixGeneticDistance2 <- foreach(i=1:length(taxaListComplete)) %do%
dist.dna(dnaBin2[[i]], model = "TN93", as.matrix = TRUE,
pairwise.deletion = TRUE)
# Specifically in Mollusca, the pairwise.deletion setting is set to FALSE.
# Convert to dataframe format.
geneticDistanceMatrixList2 <- foreach(i=1:length(taxaListComplete)) %do%
as.data.frame(matrixGeneticDistance2[i])
# Putting it into a stack (each column concatenated into one long column of
# indexes and values) so it can be easily subsetted.
geneticDistanceStackList2 <- foreach(i=1:length(taxaListComplete)) %do%
stack(geneticDistanceMatrixList2[[i]])
###################
# Section 10: Finding Appropriate Pairings According to Genetic Distance
# Criteria
# In this section, we establish preliminary pairings of BINs showing up to a
# maximum of 0.15 genetic divergence and divide preliminary pairings into
# distinct lineages.
# These values can easily be edited to add more or less stringency to the
# matches. Will produce lists with indexes (BINs, row and column names) of each
# match according to the maximum genetic distance criterion of 0.15.
pairingResultCandidates <- foreach(i=1:length(taxaListComplete)) %do%
which(geneticDistanceMatrixList2[[i]] <= 0.15)
# Next we can delete the classes that don't have any candidate pairings.
pairingResultCheck <- foreach(i=1:length(taxaListComplete)) %do%
which(length(pairingResultCandidates[[i]]) == 0)
pairingResultCheck <- which(pairingResultCheck > 0)
# Subset taxalistcomplete, geneticDistance, pairingResultCandidate, dnaStringSet
# lists according to pairingResultCheck. This is so that we aren't keeping
# classes without pairings in these lists.
if (length(pairingResultCheck > 0)) {
taxaListComplete <- taxaListComplete[-pairingResultCheck]
geneticDistanceStackList2 <- geneticDistanceStackList2[-pairingResultCheck]
pairingResultCandidates <- pairingResultCandidates[-pairingResultCheck]
dnaStringSet4 <- dnaStringSet4[-pairingResultCheck]
}
# Use these pairing results and reference against the genetic distance
# stack list to subset it.
pairingResultCandidates2 <- foreach(i=1:length(taxaListComplete)) %do%
geneticDistanceStackList2[[i]][c(pairingResultCandidates[[i]]), ]
# This command will grab the precise row and column numbers of each pairing so
# they can be used to determine a unique identifier for each pairing.
pairingResultCandidates3 <- foreach(i=1:length(taxaListComplete)) %do%
data.table(which(geneticDistanceMatrixList2[[i]] <= 0.15,
arr.ind = TRUE))
# Merge pairingResultCandidate list 2 and 3 together and combine into the
# pairing results dataframe.
dfPairingResultsL1L2 <- do.call(rbind, Map(data.frame, pairingResultCandidates2,
pairingResultCandidates3))
# Combine AllSeq with pairingResultCandidates to get all relevant taxonomic
# and latitudinal data.
dfPairingResultsL1L2 <- suppressWarnings(merge(dfPairingResultsL1L2, dfAllSeq,
by.x = "ind", by.y = "bin_uri"))
# Creating a key that can be used to uniquely identify each pairing based on its
# precise position in its respective pairwise distance matrix from the row and
# column number. This key is generated using a pairing function called
# called the Cantor pairing function which will generate a unique value
# value for each pairing.
# First adding min and max columns to the dfPairingResultsL1L2 dataframe
# so that this key can be calculated. Min refers to the min of value from
# each row/col and max refers to the max value from each row/col.
dfPairingResultsL1L2 <- transform(dfPairingResultsL1L2, max = pmax(row, col))
dfPairingResultsL1L2 <- transform(dfPairingResultsL1L2, min = pmin(row, col))
# Adding the class_taxID to the max and min value of each lineage so that
# no pairing duplicates can be present across classes.
dfPairingResultsL1L2$max <- dfPairingResultsL1L2$max +
dfPairingResultsL1L2$class_taxID
dfPairingResultsL1L2$min <- dfPairingResultsL1L2$min +
dfPairingResultsL1L2$class_taxID
# Inputting min and max into the Cantor pairing function so that a unique
# key can be created for each pairing.
dfPairingResultsL1L2$pairingKey <- 0.5 *
(dfPairingResultsL1L2$max + dfPairingResultsL1L2$min) *
(dfPairingResultsL1L2$max + dfPairingResultsL1L2$min + 1) +
dfPairingResultsL1L2$min
# order by pairingKey so all pairings are ordered correctly.
dfPairingResultsL1L2 <-
dfPairingResultsL1L2[order(dfPairingResultsL1L2$pairingKey), ]
# Changing significant digits.
options(digits =5)
# Get rid of zero ingroupdistance entries.